Background and aimsExcessive application of water and fertilizers significantly contributes to the wastage of agricultural resources and environmental pollution in arid regions. To develop appropriate irrigation and nitrogen (N) application strategies for sunflower cultivation, a two-year field experiment was conducted to investigate the effects of different irrigation levels and N application rates on sunflower yield, economic return, seed quality, water-N productivity and soil nitrate-nitrogen (NO3--N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NO}}_{3}<^>{-}\text{-N}$$\end{document}) residues.MethodsThe experiment consisted of three irrigation levels (W1, 55%-65% of field capacity (theta f); W2, 65%-75% theta f; and W3, 75%-85% theta f) and four N application rates (N0, no N application; N1, 120 kg ha-1; N2, 180 kg ha-1; and N3, 240 kg ha-1).ResultsSunflower yield, yield components, and aboveground biomass initially increased with rising irrigation levels and N application rates before stabilizing. In both growing seasons, the highest yield (5303.60 kg ha-1) and economic return (31007 CNY ha-1) was achieved in the W3N2 treatment; however, the optimal water productivity (1.54 kg m-3) and N agronomic efficiency (10.30 kg kg-1) were observed in the W2N2 treatment. Excessive applications of water and N (W3N3) did not lead to further increases in the crude fat and crude protein contents of the kernels; instead, they adversely affected oil quality. Furthermore, increasing N application from N0 to N3 led to a 183.87% rise in NO3--N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NO}}_{3}<^>{-}\text{-N}$$\end{document} accumulation within the 0-100 cm soil layer. In comparison, elevating irrigation levels from W1 to W3 reduced NO3--N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NO}}_{3}<^>{-}\text{-N}$$\end{document} accumulation by 10.10% in the 0-100 cm layer, whereas a contrasting increase of 57.53% was observed specifically in the 60-100 cm sublayer.ConclusionsA comprehensive evaluation indicated that the W2N2 treatment yielded the optimal overall benefits. Furthermore, a multiple regression model indicated that water consumption of 340.69-363.38 mm and N application rate of 154.91-191.04 kg ha-1 could effectively achieve water and fertilizer conservation while promoting high sunflower yield, quality and environmental sustainability.